U.S. patent number 5,809,374 [Application Number 08/594,494] was granted by the patent office on 1998-09-15 for process cartridge including a seal member formed from a liquid-foam material.
This patent grant is currently assigned to Canon Kabushiki Kaisha. Invention is credited to Akira Higeta, Nobuharu Hoshi, Isao Ikemoto, Kazumi Sekine, Tadayuki Tsuda, Kazushi Watanabe.
United States Patent |
5,809,374 |
Tsuda , et al. |
September 15, 1998 |
**Please see images for:
( Certificate of Correction ) ** |
Process cartridge including a seal member formed from a liquid-foam
material
Abstract
The present invention provides a process cartridge removably
mountable to a main body of an electrophotographic image forming
apparatus, the process cartridge including an electrophotographic
photosensitive member, a process device that acts on the
electrophotographic photosensitive member and has a blade member
acting on toner and a support member for supporting the blade
member, and a seal member provided for preventing the toner from
leaking from a predetermined area. The seal member is formed from
liquid-foam material to be solidified as an elastomer, and the seal
member is contacted with an edge portion of the support member.
Inventors: |
Tsuda; Tadayuki (Hachioji,
JP), Sekine; Kazumi (Kawasaki, JP),
Ikemoto; Isao (Kawasaki, JP), Watanabe; Kazushi
(Yokohama, JP), Higeta; Akira (Funabashi,
JP), Hoshi; Nobuharu (Yokohama, JP) |
Assignee: |
Canon Kabushiki Kaisha (Tokyo,
JP)
|
Family
ID: |
11898840 |
Appl.
No.: |
08/594,494 |
Filed: |
January 31, 1996 |
Foreign Application Priority Data
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|
|
|
|
Feb 2, 1995 [JP] |
|
|
7-015797 |
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Current U.S.
Class: |
399/111;
399/102 |
Current CPC
Class: |
G03G
21/1832 (20130101); G03G 2221/1648 (20130101) |
Current International
Class: |
G03G
21/18 (20060101); G03G 015/00 (); G03G
021/18 () |
Field of
Search: |
;399/102,105,107,111 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Brase; Sandra L.
Assistant Examiner: Chen; Sophia S.
Attorney, Agent or Firm: Fitzpatrick, Cella, Harper &
Scinto
Claims
What is claimed is:
1. A process cartridge, removably mountable to a main body of an
electrophotographic image forming apparatus, including an
electrophotographic photosensitive member and process means for
acting on said electrophotographic photosensitive member, said
process cartridge comprising:
a cartridge frame;
a blade member that acts on toner;
a support member for supporting said blade member; and
a seal member provided for preventing the toner from leaking from a
predetermined area,
wherein said seal member is formed from a liquid-foam material to
be solidified as an elastomer, and is spanned between an edge
corner of said support member, along a longitudinal direction
thereof, and said cartridge frame so as to prevent leakage of the
toner from said cartridge frame.
2. A process cartridge according to claim 1, wherein said blade
member is a cleaning blade member provided in said process
cartridge for removing residual toner remaining on said
electrophotographic photosensitive member, which is drum-shaped,
wherein said support member is formed from a metal sheet, and
wherein said seal member is abutted along and against said edge
corner of said support member, said edge corner being opposite, in
a short direction of said support member, to a supporting edge of
said support member supporting said blade member.
3. A process cartridge according to claim 1, wherein said blade
member is a developing blade member for regulating an amount of
toner adhered to a developing roller provided in said process
cartridge for developing a latent image formed on said
electrophotographic photosensitive member, which is drum-shaped,
wherein said support member is formed from a metal sheet, and
wherein said seal member is abutted along and against said edge
corner of said support member, said edge corner being opposite, in
a short direction of said support member, to a supporting edge of
said support member supporting said blade member.
4. A process cartridge according to claim 2 or 3, wherein said
cartridge frame includes an upper frame and a lower frame
detachably connected to said upper frame; said seal member is
formed by pouring the liquid-foam material into a groove formed in
said upper frame and said support member is attached to said lower
frame; said seal member is abutted against said edge corner of said
support member when said upper frame and said lower frame are
interconnected; and said upper frame is positioned upwardly and
said lower frame is positioned downwardly when said process
cartridge is mounted to the main body of the electrophotographic
image forming apparatus.
5. A process cartridge according to claim 2 or 3, wherein the
liquid-foam material to be solidified as the elastomer is a formed
polyurethane.
6. A process cartridge, removably mountable onto a main body of an
electrophotographic image forming apparatus, including an
electrophotographic photosensitive member; a charge member for
charging said electrophotographic photosensitive member; and a
developing roller for developing a latent image formed on said
electrophotographic photosensitive member and for supplying toner
to said electrophotographic photosensitive member by rotation of
said developing roller, said process cartridge comprising:
a cartridge frame;
a cleaning blade member made of a rubber and contacted with said
electrophotographic photosensitive member to remove residual toner
remaining on said electrophotographic photosensitive member;
a support member made of a metal sheet and attached to said
cartridge frame to support said cleaning blade member; and
a seal member provided for preventing the toner removed from said
electrophotographic photosensitive member by said cleaning blade
member from leaking between said support member and said cartridge
frame,
wherein said seal member is formed from a foamed polyurethane as
liquid-foam material to be solidified as an elastomer, and is
spanned between an edge corner of said support member, opposite in
a widthwise direction thereof to an edge of said support member
supporting said cleaning blade member, and along said edge corner
and said cartridge frame so as to prevent leakage of the toner from
said cartridge frame.
7. A process cartridge according to claim 6, wherein said cartridge
frame includes an upper frame and a lower frame detachably
connected to said upper frame; said seal member is formed by
pouring the liquid-foam material into a groove formed in said upper
frame and said support member is attached to said lower frame; said
seal member is abutted against said edge corner of said support
member when said upper frame and said lower frame are
interconnected; and said upper frame is positioned upwardly and
said lower frame is positioned downwardly when said process
cartridge is mounted to the main body of the electrophotographic
image forming apparatus.
8. A process cartridge, removably mountable onto a main body of an
electrophotographic image forming apparatus, including an
electrophotographic photosensitive member; a charge member for
charging said electrophotographic photosensitive member; and a
developing roller for developing a latent image formed on said
electrophotographic photosensitive member and for supplying toner
to said electrophotographic photosensitive member by a rotation of
said developing roller, said process cartridge comprising:
a cartridge frame;
a cleaning blade member made of a rubber contacted with said
electrophotographic photosensitive member to remove residual toner
remaining on said electrophotographic photosensitive member;
a developing blade member made of a rubber for regulating an amount
of toner adhered to said developing roller;
a support member made of a metal sheet and attached to said
cartridge frame to support said developing blade member; and
a seal member provided for preventing the toner supplied from said
developing roller from leaking between said support member and said
cartridge frame,
wherein said seal member is formed from a foamed polyurethane as
liquid-foam material to be solidified as an elastomer, and is
spanned between an edge corner of said support member, opposite in
a short direction thereof to an edge of said support member
supporting said developing blade member, and along said edge corner
and said cartridge frame so as to prevent leakage of the toner from
said cartridge frame.
9. A process cartridge according to claim 8, wherein said cartridge
frame includes an upper frame and a lower frame detachably
connected to said upper frame; said seal member is formed by
pouring the liquid-foam material into a groove formed in said upper
frame and said support member is attached to said lower frame; said
seal member is abutted against said edge corner of said support
member when said upper frame and said lower frame are
interconnected; and said upper frame is positioned upwardly and
said lower frame is positioned downwardly when said process
cartridge is mounted to the main body of the electrophotographic
image forming apparatus.
10. A process cartridge, removably mountable onto a main body of an
electrophotographic image forming apparatus, including an
electrophotographic photosensitive member; a charge member for
charging said electrophotographic photosensitive member; and a
developing roller for developing a latent image formed on said
electrophotographic photosensitive member and for supplying toner
to said electrophotographic photosensitive member by a rotation of
said developing roller, said process cartridge comprising:
a cartridge frame;
a developing blade member made of a rubber for regulating an amount
of toner adhered to said developing roller;
a developing blade support member made of a sheet metal and
attached to said cartridge frame to support said developing blade
member; and
a development seal member provided for preventing the toner
supplied from said developing roller from leaking between said
developing blade support member and said cartridge frame;
a cleaning blade member made of a rubber and contacted with said
electrophotographic photosensitive member to remove a residual
toner remaining on said electrophotographic photosensitive
member;
a cleaning blade support member made of a sheet metal and attached
to said cartridge frame to support said cleaning blade member;
and
a cleaning seal member provided for preventing the toner removed
from said electrophotographic photosensitive member by said
cleaning blade member from leaking between said cleaning blade
support member and said cartridge frame,
wherein said development seal member and said cleaning seal member
are formed from a foamed polyurethane as liquid-foam material to be
solidified as an elastomer, and said development seal member is
spanned between an edge portion of said developing blade support
member, opposite in a short direction thereof to an edge of said
developing blade support member supporting said developing blade
member, and along said edge portion of said developing blade
support member and said cartridge frame so as to be contacted with
said edge portion of said developing blade support member and said
cartridge frame, while said cleaning seal member is spanned between
an edge corner of said cleaning blade support member, opposite in a
short direction thereof to an edge of said cleaning blade support
member supporting said cleaning blade member, and along said edge
corner of said cleaning blade support member and said cartridge
frame so as to prevent leakage of the toner from said cartridge
frame.
11. A process cartridge according to claim 10, wherein said
cartridge frame includes an upper frame and a lower frame
detachably connected to said upper frame; said development seal
member and said cleaning seal member are formed by pouring the
liquid-foam material into grooves formed in said upper frame and
said developing blade support member and said cleaning blade
support member are attached to said lower frame; said development
seal member is abutted against said edge corner of said developing
blade support member and said cleaning seal member is abutted
against said edge portion of said cleaning blade support member
when said upper frame and said lower frame are interconnected; and
said upper frame is positioned upwardly and said lower frame is
positioned downwardly when said process cartridge is mounted to the
main body of the electrophotographic image forming apparatus.
12. An electrophotographic image forming apparatus to which a
process cartridge is removably mountable and which is adapted to
form an image on a recording medium, said image forming apparatus
comprising:
(a) a mounting member capable of removably mounting a process
cartridge including an electrophotographic photosensitive member
and process means for acting on said electrophotographic
photosensitive member, and having a cartridge frame, a blade member
that acts on toner, a support member for supporting said blade
member, and a seal member provided for preventing the toner from
leaking from a predetermined area, said seal member being formed
from a liquid-foam material to be solidified as an elastomer, and
said seal member being spanned between an edge corner of said
support member, along a longitudinal direction thereof, and said
cartridge frame so as to prevent leakage of the toner from said
cartridge frame;
(b) a convey member for conveying the recording medium;
(c) a transfer member for transferring, to the recording medium, a
toner image formed on said electrophotographic photosensitive
member of said process cartridge mounted to said mounting member;
and
(d) a fixing roller for fixing, to the recording medium, the toner
image transferred to the recording medium.
13. An electrophotographic image forming apparatus to which a
process cartridge is removably mountable and which is adapted to
form an image on a recording medium, said image forming apparatus
comprising:
(a) a mounting member capable of removably mounting a process
cartridge including a cartridge frame, an electrophotographic
photosensitive member, a charge member for charging said
electrophotographic photosensitive member, a developing roller for
developing a latent image formed on said electrophotographic
photosensitive member and for supplying toner to said
electrophotographic photosensitive member by rotation of said
developing roller, a cleaning blade member made of a rubber and
contacted with said electrophotographic photosensitive member to
remove residual toner remaining on said electrophotographic
photosensitive member, a support member made of a metal sheet and
attached to said cartridge frame to support said cleaning blade
member, and a seal member provided for preventing the toner removed
from said electrophotographic photosensitive member by said
cleaning blade member from leaking between said support member and
said cartridge frame, said seal member being formed from a foamed
polyurethane as liquid-foam material to be solidified as an
elastomer, and said seal member being spanned between an edge
corner of said support member, opposite in a short direction
thereof to an edge of said support member supporting said cleaning
blade member, and along said edge corner and said cartridge frame
so as to prevent leakage of the toner from said cartridge
frame;
(b) a convey member for conveying the recording medium;
(c) a transfer member for transferring, to the recording medium, a
toner image formed on said electrophotographic photosensitive
member of said process cartridge mounted to said mounting member;
and
(d) a fixing roller for fixing, to the recording medium, the toner
image transferred to the recording medium.
14. An electrophotographic image forming apparatus to which a
process cartridge is removably mountable and which is adapted to
form an image on a recording medium, said image forming apparatus
comprising:
(a) a mounting member capable of removably mounting a process
cartridge including a cartridge frame, an electrophotographic
photosensitive member, a charge member for charging said
electrophotographic photosensitive member, a cleaning blade member
made of a rubber and contacted with said electrophotographic
photosensitive member to remove residual toner remaining on said
electrophotographic photosensitive member, a developing roller for
developing a latent image formed on said electrophotographic
photosensitive member and for supplying toner to said
electrophotographic photosensitive member by a rotation of said
developing roller, a developing blade member made of a rubber for
regulating an amount of toner adhered to said developing roller, a
support member made of a metal sheet and attached to said cartridge
frame to support said developing blade member, and a seal member
provided for preventing the toner supplied from said developing
roller from leaking between said support member and said cartridge
frame, said seal member being formed from a foamed polyurethane as
liquid-foam material to be solidified as an elastomer, and said
seal member being spanned between an edge corner of said support
member, opposite in a short direction thereof to an edge of said
support member supporting said developing blade member, and along
said edge corner and said cartridge frame so as to prevent leakage
of the toner from said cartridge frame;
(b) a convey member for conveying the recording medium;
(c) a transfer member for transferring, to the recording medium, a
toner image formed on said electrophotographic photosensitive
member of said process cartridge mounted to said mounting member;
and
(d) a fixing roller for fixing, to the recording medium, the toner
image transferred to the recording medium.
15. An electrophotographic image forming apparatus to which a
process cartridge is removably mountable and which is adapted to
form an image on a recording medium, said image forming apparatus
comprising:
(a) a mounting member capable of removably mounting a process
cartridge including a cartridge frame, an electrophotographic
photosensitive member, a charge member for charging said
electrophotographic photosensitive member, a developing roller f or
developing a latent image formed on said electrophotographic
photosensitive member and for supplying toner to said
electrophotographic photosensitive member by a rotation of said
developing roller, a developing blade member made of a rubber for
regulating an amount of toner adhered to said developing roller, a
developing blade support member made of a metal sheet and attached
to a cartridge frame to support said developing blade member, a
development seal member provided for preventing the toner supplied
from said developing roller from leaking between said developing
blade support member and said cartridge frame, a cleaning blade
member made of a rubber and contacted with said electrophotographic
photosensitive member to remove a residual toner remaining on said
electrophotographic photosensitive member, a cleaning blade support
member made of a metal sheet and attached to said cartridge frame
to support said cleaning blade member, and a cleaning seal member
provided for preventing the toner removed from said
electrophotographic photosensitive member by said cleaning blade
member from leaking between said cleaning blade support member and
said cartridge frame, said development seal member and said
cleaning seal member being formed from a foamed polyurethane as
liquid-foam material to be solidified as an elastomer, and said
development seal member being spanned between an edge corner of
said developing blade support member, opposite in a short direction
thereof to an edge of said developing blade support member
supporting said developing blade member, and along said edge corner
of said developing blade support member and said cartridge frame so
as to prevent leakage of the toner from said cartridge frame, while
said cleaning seal member is spanned between an edge portion of
said cleaning blade support member, opposite in a short direction
thereof to an edge of said cleaning blade support member supporting
said cleaning blade member, and along said edge portion of said
cleaning blade support member and said cartridge frame so as to be
contacted with said edge portion of said cleaning blade support
member and said cartridge frame;
(b) a convey member for conveying the recording medium;
(c) a transfer member for transferring, to the recording medium, a
toner image formed on said electrophotographic photosensitive
member of said process cartridge mounted to said mounting member;
and
(d) a fixing roller for fixing, to the recording medium, the toner
image transferred to the recording medium.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a process cartridge for forming an
image by utilizing developer (referred to as "toner" hereinafter)
and an electrophotographic image forming apparatus to which such a
process cartridge is mounted to form the image.
The process cartridge incorporates an electrophotographic
photosensitive member and at least one of cleaning means and
developing means and can be removably be mounted to the
electrophotographic image forming apparatus. The
electrophotographic image forming apparatus may be, for example, a
laser beam printer, a copying machine, a facsimile system, a word
processor and the like.
2. Description of the Related Art
In electrophotographic image forming apparatuses such as printers,
an electrophotographic photosensitive member which is uniformly
charged by a charger is selectively exposed to form a latent image.
Then, the latent image is visualized by a developing device as a
toner image which is in turn transferred onto a recording medium,
thereby executing recording of the image. In such apparatuses,
conventionally, the maintenance of various parts are performed by
expert persons.
To avoid this, for example, as shown in FIG. 18, there has been
proposed a technique in which a process cartridge is constituted by
a cartridge frame obtained by interconnecting upper and lower
frames 51, 50 and an electrophotographic photosensitive member 52,
a charger 53, a developing device 54 and a cleaning device 55 are
contained within the cartridge frame to form a cartridge unit. By
exchanging the used cartridge unit with a new one by an operator,
the cartridge in which the toner is used up or consumed and/or the
service life of the electrophotographic photosensitive member and
the like is expired can easily be changed and the maintenance can
be facilitated.
The cleaning device 55 has a waste toner containing portion 55a for
collecting the waste toner removed from the electrophotographic
photosensitive member 52, and the waste toner containing portion
55a is defined by engaging a plurality of elements such as the
upper and lower frames 51, 50 and a cleaning blade 55b and the like
with each other. Further, the developing device 54 has a developing
toner containing portion 54a for supplying the toner to the
electrophotographic photosensitive member 52, and the developing
toner containing portion 54a is defined by engaging a plurality of
elements such as the upper and lower frames 51, 50 and a developing
blade 54b and the like with each other.
A seal member 56 made of foamed polyurethane or the like is
provided in each engagement portion between the elements so that
the seal member is firmly contacted with the elements. In this way,
the toner can be prevented from leaking from the waste toner
containing portion 55a of the cleaning device 55 and the developing
toner containing portion 54a of the developing device 54.
By the way, the inventors have proposed a technique in which such a
seal member is formed by using liquid-foam material which can be
cured as elastomer (refer to U.S. Pat. No. 5,208,643). This
technique is very effective in practical use.
The present invention relates to an improvement in this
technique.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a process
cartridge and an electrophotographic image forming apparatus to
which such a process cartridge can be removably mounted, wherein
repelling forces of seal members can be suppressed.
Another object of the present invention is to provide a process
cartridge and an electrophotographic image forming apparatus using
such a process cartridge, wherein deformation of parts or elements
caused by repelling forces of seal members can be prevented and a
sealing ability between each seal member and the elements contacted
therewith can be improved without having to increase the strength
of each element and without having to make each element bulky.
A further object of the present invention is to provide a process
cartridge and an electrophotographic image forming apparatus,
wherein seal members are formed by using liquid-foam material which
can be cured as an elastomer and the seal members are disposed in
contact with edge portions of blade support members.
Another object of the present invention is to provide a process
cartridge and an electrophotographic image forming apparatus,
wherein, by urging edge portions of blade support members against
seal members, even if great repelling forces are generated when the
seal members are compressed, influence of the repelling forces can
be reduced, thereby preventing deformation of parts.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic sectional view of a process cartridge
according to a first embodiment of the present invention;
FIG. 2 is a schematic sectional view of an image forming apparatus
within which the process cartridge is mounted;
FIG. 3 is a perspective view for explaining mounting of the process
cartridge;
FIG. 4 is a perspective view for explaining formation of seal
members by pouring liquid-foam material;
FIG. 5 is a flow chart for explaining the formation of the seal
member by pouring the liquid-foam material;
FIG. 6 is an exploded sectional view of the process cartridge
showing a condition that upper and lower frames are separated from
each other;
FIG. 7 is an explanatory view for showing a positional relation
between the seal members and blade support members;
FIG. 8 is a graph showing a relation between a repelling force and
a collapse amount when the seal member is pressed;
FIGS. 9A and 9B are explanatory views showing a blade support
member having a protruded portion;
FIG. 10 is a perspective view showing a seal arrangement according
to an embodiment of the present invention in which a central area
(in a longitudinal direction) of an edge portion of a blade support
member is urged against a seal member;
FIG. 11 is an explanatory view for showing a positional relation
between the seal members and the blade support members in the
embodiment of FIG. 10;
FIG. 12 is a sectional view of a process cartridge according to an
embodiment of the present invention in which locking means is
provided in the vicinity of a seal members;
FIG. 13 is a sectional view of a process cartridge according to an
embodiment of the present invention in which seal members are urged
against each other to provide a sealing function;
FIG. 14 is an exploded sectional view of the process cartridge of
FIG. 13 showing a condition that upper and lower frames are
separated from each other;
FIG. 15 is a graph showing a relation between a repelling force and
a collapse amount when the seal member is prepared, in the process
cartridge of FIG. 13;
FIG. 16 is a sectional view of a process cartridge according to an
embodiment of the present invention in which seal members are
protruded in a direction perpendicular to an engagement
direction;
FIG. 17 is a sectional view of a process cartridge according to an
embodiment of the present invention in which seal members are urged
against associated members in a laid condition; and
FIG. 18 is a sectional view of a conventional process
cartridge.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention will now be explained in connection with
embodiments thereof with reference to the accompanying
drawings.
First Embodiment
First of all, a process cartridge and an electrophotographic image
forming apparatus to which such a process cartridge can removably
be mounted according to a first embodiment of the present invention
will be explained with reference to FIGS. 1 to 10. Incidentally,
FIG. 1 is a schematic sectional view of a process cartridge
according to the first embodiment of the present invention, FIG. 2
is a schematic sectional view of an electrophotographic image
forming apparatus within which the process cartridge is mounted,
FIG. 3 is a perspective view for explaining mounting of the process
cartridge, and FIGS. 4 to 10 are views for explaining a seal
arrangement.
Now, entire constructions of the process cartridge and the image
forming apparatus having such a process cartridge will be firstly
explained, and then, seal arrangements in a waste toner containing
portion of a cleaning means and a developing toner containing
portion of a developing means will be explained.
<Entire Construction>
As shown in FIG. 2, in the electrophotographic image forming
apparatus (for example, laser beam printer) A, information light
(corresponding to image information) from an optical system 1 is
illuminated on a drum-shaped electrophotographic photosensitive
member 8 to form a latent image, and the latent image is then
developed to form a toner image. On the other hand, synchronously
with the formation of the toner image, a recording medium 2 is
supplied and conveyed from a cassette 3a by a convey means 3
comprising a pick-up roller 3b, a reverse rotation roller 3c and
pinch rollers 3c1, 3c2, 3c3 urged against the reverse rotation
roller and driven by rotation of the reverse rotation roller. When
the recording medium 2 reaches the electrophotographic
photosensitive member 8 incorporated into a process cartridge B, by
applying voltage to a transfer roller (transfer means) 4, the toner
image formed on the electrophotographic photosensitive member is
transferred onto the recording medium 2. After the transferring of
the toner image, the recording medium 2 is sent to fixing means 5
comprising a fixing rotary member 5b having a heater 5a therein and
a drive roller 5c for urging the recording medium 2 against the
fixing rotary member 5b to convey the recording medium. In the
fixing device 5, the toner image is permanently fixed to the
recording medium 2. Thereafter, the recording medium 2 is conveyed
by a pair of discharge rollers 3d1, 3d2 and a pair of discharge
rollers 3e1, 3e2 and is discharged into a discharge portion 7
through a reverse rotation convey path 6.
The process cartridge B further includes at least one process
means, as well as the electrophotographic photosensitive member.
The process means may, for example, be charge means for charging
the electrophotographic photosensitive member, developing means for
developing the latent image formed on the electrophotographic
photosensitive member and/or cleaning means for cleaning or
removing the residual toner remaining on the electrophotographic
photosensitive member. In the illustrated embodiment, as shown in
FIG. 1, in the process cartridge B, the electrophotographic
photosensitive member, i.e., photosensitive drum 8 having a
photosensitive layer thereon is rotated; meanwhile, a surface of
the photosensitive drum 8 is uniformly charged by applying voltage
to the charger (charge means) 9. Then, the photosensitive drum 8 is
exposed by the information light from the optical system 1 through
an exposure portion, thereby forming the latent image. The latent
image is then developed by the developing means 10.
In the developing means 10, toner contained in a developing toner
containing portion 10a is fed by a toner feed member 10b to a
rotating developing roller 10d having a fixed magnet 10c therein.
Then, a toner layer is formed on a surface of the developing roller
10d by a developing blade 10e while applying frictional charge to
the toner layer. By transferring the toner from the toner layer to
the latent image formed on the photosensitive drum 8, the latent
image is visualized as a toner image. After the toner image is
transferred onto the recording medium 2 by applying to the transfer
roller 4 voltage having polarity opposite to that of the toner
image, the residual toner remaining on the photosensitive drum 8 is
removed from the photosensitive drum 8 by the cleaning means 11
comprising a cleaning blade 11a for scraping the residual toner
away from the drum, a dip sheet 11b for receiving the removed toner
(waste toner) and a waste toner containing portion 11c for
collecting the waste toner.
Incidentally, the above-mentioned various elements such as the
photosensitive drum are housed and supported within a housing
obtained by interconnecting upper and lower frames 13, 12 to each
other, thereby providing a cartridge which can removably be mounted
to a cartridge mounting means provided within a body 14 of the
apparatus.
Regarding the cartridge mounting means, as shown in FIG. 3, when an
open/close member 14a is opened, there is provided a cartridge
mounting space within the apparatus body 14, and a pair of
cartridge mounting guide portions 15 are formed on inner side
surfaces of the apparatus body 14. Each guide portion 15 includes
first and second guide rails 15a, 15b for guiding the insertion of
the process cartridge B. On the other hand, the process cartridge B
is provided at its outer side surfaces with cylindrical projections
15c each protruding outwardly in alignment with a rotation axis of
the photosensitive drum 8 and having a radius substantially the
same as a radius of a recessed portion 15a1 of each first guide
rail 15a, and guide ridges 15d contiguous to the respective
cylindrical projections 15c. Further, an engagement portion 15e is
formed on a lower portion of a front (in a cartridge inserting
direction) surface of the process cartridge B.
When the process cartridge B is mounted to the apparatus body, the
process cartridge B is inserted into the cartridge mounting space
while guiding the cylindrical projections 15c and the guide ridges
15d by means of the first guide rails 15a and guiding the
engagement portion 15e by means of the second guide rails 15b.
Then, by closing the open/close member 14a, the mounting of the
process cartridge B to the image forming apparatus A is
completed.
<Seal Arrangements for Waste Toner Containing Portion and the
like>
Now, seal arrangements for the waste toner containing portion and
the like will be explained. As shown in FIG. 1, the waste toner
containing portion 11c is bordered by the upper and lower frames
13, 12, cleaning blade 11a, dip sheet 11b and photosensitive drum
8. In this case, the cleaning blade 11a and the dip sheet 11b are
urged against the photosensitive drum 8, and a plurality of
elements including the upper frame 13, lower frame 12 and cleaning
blade 11a are engaged with each other. And, seal members 16 are
provided in engagement portions between these elements, thereby
preventing the toner from leaking through the engagement
portions.
On the other hand, as shown in FIG. 1, the developing toner
containing portion 10a is bordered by the upper and lower frames
13, 12, developing roller 10d and developing blade 10e. In this
case, the developing blade 10e is urged against the developing
roller 10d, and a plurality of elements including the upper frame
13, lower frame 12 and developing blade 10e are engaged with each
other. And, seal members 17 are provided in engagement portions
between these elements, thereby preventing the toner from leaking
through the engagement portions.
As shown in FIG. 4 (showing a condition that the upper frame 13 is
opened to show the interior thereof), the seal members 16, 17 are
formed from liquid-foam material (for example, foamed polyurethane)
which can be cured or solidified as elastomer, which liquid-foam
material is injected from a nozzle 18 into grooves 13c formed in
the upper frame 13. The seal member 16 includes seal portions 16a,
16b attached to the upper frame 13 to encircle the waste toner
containing portion 11c, and the seal member 17 includes seal
portions 17a, 17b attached to the upper frame 13 to encircle the
developing toner containing portion 10a.
Next, an example of a method for coating the seal member will be
explained. First of all, as shown in FIG. 5, the frame is manually
picked up from a box and is mounted on a pallet for conveyance
(conveying pallet), and the frame together with the conveying
pallet is conveyed to a position where it is associated with a
robot for coating (coating robot) by means of a robot for
conveyance (conveying robot). Thereafter, the frame is clamped by a
frame clamping means of the conveying robot and then is mounted on
a pallet for coating (coating pallet). Then, the coating pallet is
conveyed to a coating position by means of the coating robot.
Then, a signal is transmitted from the coating robot to an
injecting device, with the result that the coating of liquid-foam
elastomer is effected. When the coating process is finished, the
frame clamping means of the conveying robot picks up the frame
again, and the frame is mounted on the conveying pallet again while
reversing upper face/lower face. The frame mounted on the conveying
pallet with the reversed upper face/lower face is conveyed for
about 30 minutes; meanwhile, the liquid-foam elastomer is
solidified to an extent that it is does not adhere to an operator's
fingers. Further, during the conveyance of the frame for about 30
minutes, a temperature/humidity condition is maintained to permit
adequate foaming. Thereafter, the frame is manually packed in a
box.
In this way, since the formation of the seal members can be
automated by using the coating system, the assembling of the
process cartridge can be facilitated and the manufacturing cost can
be reduced, with the result that the running cost of the image
formation can be reduced.
The cleaning blade 11a comprises a support member 11a1 formed from
a plate member (such as a metal sheet) having a thickness of about
1-2 mm, and a blade member 11a2 made of rubber and attached to a
tip end of the support member. As shown in FIG. 6, the support
member 11a1 is secured to the lower frame 12 by screws and the
like, and the blade member 11a2 is urged against the photosensitive
drum 8 to remove the residual toner remaining on the photosensitive
drum 8.
The developing blade 10e is similar to the cleaning blade 11a.
Thus, the developing blade 10e comprises a support member 10e1
formed from a plate member (such as a metal sheet) having a
thickness of about 1-2 mm, and a blade member 10e2 made of rubber
and attached to a tip end of the support member. The support member
10e1 is secured to the lower frame 12 by screws and the like, and
the blade member 10e2 is urged against the developing roller 10d to
regulate the thickness of the toner layer formed on the rotating
developing roller 10d.
After the seal members 16, 17 are coated in-this way and the blades
11a, 10e are attached to the frame, the frames 12, 13 are connected
to each other by fitting locking pawls 13a formed on the upper
frame 13 into locking holes 12a formed in the lower frame 12 and by
threading screws 19 into threaded holes 12b, 13b.
In this case, as shown in FIG. 7 (which is a plan view showing the
interior of the upper frame 13 and further showing a positional
relation between the seal members 16, 17, cleaning blade 11a and
developing blade 10e), the cleaning blade 11a is attached so that a
tip edge portion 11a3 of the support member 11a1 of the cleaning
blade 11a is urged against the seal member 16. Similarly, the
developing blade 10e is attached so that a tip edge portion 10e3 of
the support member 10e1 of the developing blade 10e is urged
against the seal member 17. That is to say, in a widthwise
direction of the support members, longitudinal edges of the blade
support members 10e1, 11a1 opposite to edges supporting the blades
10e2, 11a2 are urged against the seal members 17, 16.
As mentioned above, the seal members 16, 17 are formed from the
liquid-foam elastomer which can be solidified as elastomer. Thus,
repelling forces of the seal members when compressed become greater
than that of molt plane which is conventionally used as a seal
member, since skin layers are remaining on the seal members.
However, as mentioned above, by urging the edge portions of the
blade support members against the seal members, when the seal
members 16, 17 are compressed, the repelling forces can be reduced.
Now, the reduction of the repelling force will be explained with
reference to a graph shown in FIG. 8.
In the graph of FIG. 8, the abscissa indicates a collapse amount of
the seal member (1-3 mm/5 mm) and the ordinate indicates the
repelling force (gf/5 mm) in association with such a collapse
amount. Further, a curve (1) indicates a result obtained when the
seal member formed by pouring the liquid-foam material as is in the
illustrated embodiment is face-pressed by the blade support member,
a curve (2) indicates a result obtained when the seal member formed
by pouring the liquid-foam material as in the illustrated
embodiment is edge-pressed by the edge portion of the blade support
member, and a curve (3) indicates a result obtained when a seal
member comprised of molt plane (SM55; thickness of 3 mm) as in the
conventional case is face-pressed by a blade support member.
As can be understood from the graph of FIG. 8, in comparison with
the repelling force (curve (3)) generated when the conventional
seal member (molt plane) from which the skin layer was removed is
face-pressed, the repelling force (curve (1)) generated when the
seal member with the skin layer as in the illustrated embodiment is
face-pressed is greater by five times or more, regarding the
collapse amount of 1 mm. However, the repelling force (curve (2))
generated when the seal member is collapsed or pressed by the edge
of the blade support member (such as a metal sheet) is reduced to
half or less in comparison with the repelling force of the curve
(1) (face-pressing). This is the reason why, even if the collapse
amount of the seal member when face-pressed is the same as the
collapse amount of the seal member when edge-pressed, the volume
change ratio of the seal member when face-pressed is smaller than
that when edge-pressed, with the result that the repelling force of
the seal member when edge-pressed becomes smaller than that when
face-pressed.
As a result of tests, regarding the seal member formed by pouring
the liquid-foam material as in the illustrated embodiment, since
the sealing ability is substantially the same so long as the
collapse amount is the same, it was found that the repelling force
can be reduced without worsening the sealing ability, by urging the
edge portions of the blade support members against the seal member
as in the illustrated embodiment.
Accordingly, in the illustrated embodiment, since the repelling
forces of the seal members 16, 17 are reduced, it is possible to
prevent the deformation of the upper frame due to the repelling
force, to closely contact the seal members 16, 17 with the upper
frame 13 and the blade support members 11a1, 10e1 and to prevent
the leakage of the toner. Further, the deformation of the blade
support members 11a1, 10e1 can be prevented, and the poor cleaning
and the uneven thickness of the toner layer can also be
prevented.
With the arrangement as is in the illustrated embodiment, when the
contact areas between the blade support members 11a1, 10e1 and the
seal members are long, it is particularly effective to prevent the
deformation of a central portion (in a longitudinal direction) of
the upper frame 13.
Incidentally, in the illustrated embodiment, while an example that
edge portions of the blade support members 11a1, 10e1 for both of
the cleaning blade 11a and the developing blade 10e are urged
against the seal members was explained, regarding either the
cleaning blade 11a or the developing blade 10e, the tip edge
portion of the support member may be urged against the seal
member.
Further, in the illustrated embodiment, while an example that the
edge portions of the blade support members 11a1, 10e1 are urged
against the seal members 16, 17 was explained, as shown in FIGS. 9A
and 9B, protruded portions 11a4, 10e4 extending in a longitudinal
direction may be formed on upper surfaces of the blade support
members 11a1, 10e1 and such protruded portions 11a4, 10e4 may be
urged against the seal members 16, 17. When the blade support
members 11a1, 10e1 are press-worked from sheet metal, the protruded
portions 11a4, 10e4 can easily be formed by the drawing operation.
Alternatively, when the blade support members 11a1, 10e1 are formed
by extrusion, the protruded portions 11a4, 10e4 can easily be
obtained by providing protruded areas in extrusion dies. When the
blade support members 11a1, 10e1 are formed from resin, the
protruded portions 11a4, 10e4 can easily be obtained by
injection-molding them to provide the protruded portions.
In this way, when the protruded portions 11a4, 10e4 formed on the
blade support members 11a1, 10e1 are urged against the seal members
16, 17, the same advantage as that when the edge portions of the
blade support members are urged against the seal members can be
achieved.
Further, in the illustrated embodiment, while an example that the
entire longitudinal edge portions of the blade support members
11a1, 10e1 are urged against the seal members 16, 17 or the
longitudinal protruded portions formed on the blade support members
along their entire lengths are urged against the seal members 16,
17 was explained, only a central edge portion or a central
protruded portion (in a longitudinal direction) of each blade
support member may be urged against the corresponding seal member.
For example, as shown in FIGS. 10 and 11, a seal portion 16a of the
seal member 16 which is to be contacted with the cleaning blade
support member 11a1 is formed to be trapezoidal, and a central edge
portion 11a3 of the support member 11a1 is urged against the seal
member 16 (edge-pressing) and both end portions of the support
member 11a1 is urged against the seal member (face-pressing).
If the upper frame 13 is deformed by the repelling force of the
seal member, the influence of the repelling force is great at the
longitudinal central portion of the frame. Thus, only at the
longitudinal central portion, which is apt to be subjected to the
influence of the repelling force, is the edge portion 11a3 of the
support member 11a1 urged against the seal member 16
(edge-pressing).
Also with this arrangement, the repelling force of the seal member
can be reduced and the deformation of the upper frame 13 can be
prevented. Incidentally, while FIGS. 10 and 11 showed the cleaning
blade 11a, it should be noted that a similar arrangement can be
applied to the developing blade 10e.
Second Embodiment
In the above-mentioned first embodiment, while an example that the
repelling forces of the compressed seal members are reduced by
edge-pressing the edge portions of the blade support members
against the seal members to prevent the deformation of the upper
frame 13 was explained, a second embodiment in which the
deformation of the upper frame 13 due to the repelling forces of
the seal members can be prevented will be explained with reference
to FIG. 12. Incidentally, in the second embodiment, since the
fundamental construction of a process cartridge B is substantially
the same as that of the first embodiment, elements having the same
function as those in the first embodiment are designated by the
same reference numerals and explanation thereof will be omitted.
Further, since an image forming apparatus to which the process
cartridge B according to the second embodiment is mounted is
substantially the same as the image forming apparatus explained in
connection with the first embodiment, detailed explanation of the
image forming apparatus will be omitted.
In the second embodiment, as shown in FIG. 12, locking pawls
(connecting means) 20 are formed on an inner upper surface of the
upper frame 13 constituting a part of the waste toner containing
portion 11c in the vicinity of the engagement portion between the
seal member 16 and the blade support member 11a1 so that, when the
upper and lower frames 13, 12 are interconnected, the locking pawls
20 are locked to the blade support member 11a1.
With this arrangement, even if the upper frame 13 tries to be
deformed upwardly due to the repelling force of the seal member 16,
the deformation of the upper frame is prevented by the locking
pawls 20. Accordingly, the seal member 16 is closely contacted with
the upper frame 13 and the blade support member 11a1, thereby
preventing leakage of toner.
Further, regarding the developing blade 10e, the same arrangement
as mentioned above can be adopted. That is to say, locking pawls
(connecting means) 21 are formed on an inner upper surface of the
upper frame 13 constituting a part of the developing toner
containing portion 10a in the vicinity of the engagement portion
between the seal member 17 and the blade support member 10e1 so
that, when the upper and the lower frames 13, 12 are
interconnected, the locking pawls 21 are locked to the blade
support member 10e1.
With this arrangement, as in the waste toner containing portion,
the deformation of the upper frame 13 due to the repelling force of
the seal member 17 can be prevented. Thus, the seal member 17 is
closely contacted with the upper frame 13 and the blade support
member 10e1, thereby preventing leakage of toner.
Incidentally, in the embodiment shown in FIG. 12, while an example
that the locking pawls 20, 21 are locked to the blade support
members 11a1, 10e1 having relatively great strength was explained,
the present invention is not limited to such an example, but, any
members for connecting the parts may be provided between the parts
in the vicinity of the seal members 16, 17 and the locking pawls
20, 21 may be locked to such members.
Third Embodiment
Next, a third embodiment of the present invention in which the
repelling forces of the seal members can be reduced will be
explained with reference to FIGS. 13 to 17. Incidentally, also in
this case, since the fundamental construction of a process
cartridge B is substantially the same as that of the first
embodiment, elements having the same function as those in the first
embodiment are designated by the same reference numerals and
explanation thereof will be omitted. Further, since an image
forming apparatus to which the process cartridge B according to the
third embodiment is mounted is substantially the same as the image
forming apparatus explained in connection with the first
embodiment, detailed explanation of the image forming apparatus
will be omitted.
In this third embodiment, as shown in FIGS. 13 and 14, there is a
seal portion 16a of the seal member 16 (formed from the liquid-foam
material) on an inner surface of the upper frame 13 constituting a
part of the waste toner containing portion 11c in a confronting
relation to the cleaning blade support member 11a1. In this case,
the seal portion 16a is shaped (from the liquid-foam material) to
be convex toward a direction from which the upper frame 13 is
engaged by the blade support member 11a1 (i.e., the downward
direction in FIG. 13).
On the other hand, a seal member 22 is formed (from liquid-foam
material in the same manner as the seal member 16) on an upper
surface of the cleaning blade support member 11a1 in a confronting
relation to the seal portion 16a. In this case, the seal member 22
is shaped (from the liquid-foam material) to be convex toward a
direction from which the blade support member 11a1 is engaged by
the upper frame 13 (i.e., the upward direction in FIG. 13).
When the waste toner containing portion 11c is formed by
interconnecting the upper and lower frames 13, 12, the seal portion
16a of the seal member 16 and the seal member 22 are engaged by
each other to form a seal. In this way, by forming the seal by
urging the seal members against each other, the repelling forces of
the seal members can be further reduced, in comparison with the
case where the seal is formed by face-pressing the blade support
member against the seal member formed from the liquid-foam material
(which can be solidified as elastomer). The reduction of the
repelling force will now be explained with reference to a graph
shown in FIG. 15.
In the graph of FIG. 15, the abscissa indicates a collapse amount
of the seal member (1-3 mm/5 mm) and the ordinate indicates the
repelling force (gf/5 mm) in association with such a collapse
amount. Further, a curve (1) indicates a result obtained when the
seal member formed by pouring the liquid-foam material as is in the
illustrated embodiment is face-pressed by the blade support member,
a curve (2) indicates a result obtained when the seal members
formed by pouring the liquid-foam material as is in the illustrated
embodiment are urged against each other, and a curve (3) indicates
a result obtained when a seal member comprised of molt plane (SM55;
thickness of 3 mm) as in the conventional case is face-pressed by a
blade support member (Incidentally, the curves (1) and (3) are the
same as the curves (1) and (3) shown in FIG. 8 regarding the first
embodiment).
As explained in connection with the first embodiment, in comparison
with the repelling force (curve (3)) generated when the
conventional seal member (molt plane) is face-pressed, the
repelling force (curve (1)) generated when the seal member is
face-pressed is greater by five times or more, regarding the
collapse amount of 1 mm. However, the repelling force (curve (2))
generated when the seal members are urged against each other is
reduced to half or less in comparison with the repelling force of
the curve (1) (face-pressing). This is the reason why, even when
the collapse amounts are the same, the volume change ratio of the
seal members when urged against each other is smaller than that
when face-pressed, with the result that the repelling forces of the
seal members when urged against each other becomes smaller than
that when face-pressed.
Accordingly, in the third embodiment, since the repelling force of
the seal member 16 is reduced, it is possible to prevent the
deformation of the upper frame 13 due to the repelling force, to
closely contact the seal member 16 with the upper frame 13 and the
blade support members 11a1 and to prevent the leakage of the toner.
Further, the deformation of the blade support members 11a1 can be
prevented, and the poor cleaning and the uneven thickness of the
toner layer can also be prevented.
Incidentally, in the embodiment shown in FIG. 13, while an example
that the seal members 16, 22 are convex toward the engagement
direction between the upper frame 13 and the blade support member
11a1 was explained, as shown in FIG. 16, the seal portion 16a of
the seal member 16 and the seal member 22 engaged by the seal
portion may be convex toward a direction (left/right direction in
FIG. 16) perpendicular to the engagement direction (up/down
direction in FIG. 16) between the upper frame 13 and the blade
support member 11a1. With this arrangement, when the upper frame 13
and the blade support member 11a1 are engaged by each other in the
up/down direction, the repelling force generated by the urging
between the seal members 16, 22 can be further reduced, thereby
preventing the deformation of the upper frame 13 due to the
repelling force and further improving the prevention of leakage of
toner.
Further, in the embodiment shown in FIG. 13, while an example that
the seal is formed by urging the seal members against each other
was explained, as shown in FIG. 17, the seal portion 16a of the
seal member 16 may be formed on one of the upper frame 13 and the
blade support member 11a1 which are to be engaged by each other (in
the illustrated embodiment, the seal portion is formed on the upper
frame 13), and the seal portion 16a may be convex toward a
direction perpendicular to the engagement direction (up/down
direction in FIG. 17) so that the seal portion is laterally urged
against the blade support member 11a1 to cause lateral deformation
of the seal portion.
Also in this case, the repelling force of the seal portion 16a in
the engagement direction can be reduced to prevent the camber
(deformation) of the upper frame 13, thereby improving the sealing
feature in the engagement portion to prevent the leakage of
toner.
Incidentally, in FIG. 17, while an example that the seal portion
16a is urged against the support member 11a1 was shown,
alternatively, the seal portion may be provided on the support
member 11a1 so that the seal portion is urged against the upper
frame. Also in this case, the same advantages can be obtained.
Further, in the embodiment shown in FIG. 17, while the waste toner
containing portion 11c was explained, as is in the above-mentioned
embodiment, the same arrangement can be adopted to the engagement
portion between the upper frame 13 constituting a part of the
developing toner containing portion 10a and the developing blade
support member 10e1. Also in this case, the same advantages can be
obtained.
Further, the seal arrangement as shown in the third embodiment can
be applied to any engagement portions between plural elements
constituting a part of the toner containing portion, as well as the
engagement portions between the frame and the blade support member.
Also in this case, the same advantage can be obtained.
Other Embodiments
Next, other embodiments regarding various elements constituting the
process cartridge will be explained.
The process cartridge B according to the above-mentioned
embodiments is not limited to mono-color image formation, but, a
plurality of developing means each including different color toner
may be provided in the process cartridge to form a plural color
image (for example, two-color image, three-color image or
full-color image).
Further, a developing method used with the developing means may be
a conventional two-component magnet brush developing method, a
cascade developing method, a touch-down developing method, a cloud
developing method or the like.
The photosensitive member is not limited to the photosensitive
drum, but may be, for example, as follows. The photosensitive body
is constituted by photo-conductor which may be, for example,
amorphous silicone, amorphous selenium, zinc oxide, titanium oxide,
organic photo-conductor (OPC) or the like. Further, the
photosensitive body can be mounted on a rotary member such as a
drum, a belt and the like, or a sheet. Incidentally, in general,
the drum or the belt is used. For example, in the drum-type
photosensitive member, the photo-conductor is deposited or coated
on an aluminium alloy cylinder and the like.
In the first embodiment, while an example that the charge means
comprises a charger in which three walls formed from tungsten wires
are covered by metallic shields such as aluminium was explained, a
so-called contact charging method wherein a charge roller rotated
by rotation of the photosensitive drum is contacted with the
photosensitive drum and the photosensitive drum is charged by
applying voltage to the charge roller may be used.
Incidentally, the charge means may be of a blade (charge blade)
type, pad type, block type rod type or wire type, as well as a
roller type.
Further, the cleaning means for removing the residual toner from
the photosensitive drum may comprise a blade, a fur brush or a
magnet brush.
The process cartridge incorporates therein an electrophotographic
photosensitive member, a toner containing portion and at least one
process means. Accordingly, other than the above-mentioned process
cartridge, the process cartridge may incorporate therein an
electrophotographic photosensitive member and a developing means as
a unit which can removably be mounted to an image forming
apparatus, or may incorporate therein an electrophotographic
photosensitive member and a cleaning means as a unit which can
removably be mounted to an image forming apparatus, or may
incorporate therein an electrophotographic photosensitive member, a
developing means or a cleaning means, and a charge means as a unit
which can removably be mounted to an image forming apparatus.
Further, in the above-mentioned embodiment, while an example that
the image forming apparatus is embodied as a laser beam printer was
explained, the present invention is not limited to such an example,
but may be, for example, an electrophotographic copying machine, a
facsimile system, a word processor or the like.
As mentioned above, according to the present invention, since the
seal member(s) are urged or pressed by the edge portion(s) of the
blade support member(s), even when the seal member generating great
repelling force when compressed is used, the influence of the
repelling force of the seal member can be reduced.
* * * * *